Many mothers are anxious to know how far the senses of the infant have developed when it enters the world. This problem has stimulated some scientific investigation, though hardly so much as its interest would justify. Two lines of inquiry have been pursued toward its solution. The objective point of one of these has been to determine how nearly the sense organs of the newborn correspond anatomically to those of an adult; that is how perfectly has their organization been completed. The other has been to learn how the infant reacts when the various senses are stimulated; the interpretation of these reactions is, however, particularly liable to error and sometimes amounts only to guesswork. The organization of the nerves and muscles in the eye is far from perfect at the time of birth. The muscles act irregularly; indeed, the lack of muscular adjustment is such that movements of the eye likely to alarm the parents are regularly observed in very young infants. Furthermore they cannot focus images which fall upon their eyes. The retina, which receives visual impressions, has reached such development at birth, however, that sensations of light can be perceived. For example, if a lamp is suddenly flashed before the face of a newly born baby it cries. From this and similar evidence, indicating that strong light irritates the delicate structures of the eye, we have learned that a nursery should not be illuminated, during the day or night, so brightly as the rooms adults occupy. Certainly several weeks, and probably several months, pass before an infant can see anything save as blurs of light and darkness. Objects, such as a hand, probably appear as shadows, which are not correctly interpreted until late in infancy. In regard to color vision we have as yet no reliable information concerning children under two years of age. Infants of less than a year have been known to distinguish certain colored papers. But such discrimination is probably due to a difference in brightness of the colors.